A collection of more than 12,000 shoes, displayed in a building shaped like a shoebox.

Known as "Toronto's Flatiron."

An abandoned 1970s theme park that has been turned into a space for waterfront walking.

One of the largest underground systems runs under Canada's largest urban center.

This urban oasis is a marvelous meld of music and landscape architecture.

This nine-story building is the oldest standing skyscraper in D.C.

A fantastic place to see murals, and an important location in the history of Toronto's legal street art scene.

The Incredible Hulk, Yoda, Mulder and Scully, and many many others watch over the mean streets of Toronto.

This whimsical fountain pays tribute to Toronto's four-legged friends.

The innocent intentions of this monument are somewhat lost in the sculpture's muscled imagery.

Legend has it that President Grant’s frequent drinking in the lobby gave rise to the term “lobbyist.”

D.C. once had its own tiny rival to the New York Stock Exchange.

The winding route passes through an enclosed alleyway, two tunnels, and leads to the White House basement.

These unusual rooms on wheels are holdovers from the 1960s.

Berlin's old airport.

This platform is now a memorial dedicated to those who were deported during the Holocaust.

An imperial church bombed to ruins during WWII now stands as a jagged memorial.

This concrete residential area doubles as an open-air gallery.

A brush maker used his factory to protect blind Jews from the Gestapo.

On the Spree bank, discover one of the last reminders of a symbolic wall that divided, and was torn down by the people.

An abandoned NSA listening post on Berlin's "Devil's Mountain."

A narrow passage next to a cafe leads to a courtyard exploding with murals, tags, and paste-ups.

A museum dedicated to the history of a terrifying secret police is now held in their former headquarters.

A tour of underground Berlin takes you through WWII air raid shelters and tunnels used to smuggle people out of East Germany.